1. Field of the Invention
This invention pertains to a portable vertical lift, as may be used to lift wheelchair-bound hunters into trees. As our society progresses, the number of activities which are accessible to the physically disadvantaged or in which the physically disadvantaged desire to participate is also increasing. Sports for the wheelchair-bound, such as racing and basketball, are no exception to this trend, and hunting is included among these sports. However, as in many of these cases, the physically disadvantaged present unique needs and special devices are required to allow their full participation. For example, consider the case of a physically disadvantaged hunter who is confined to a wheelchair. It is common for hunters to construct a tree stand in a tree and then wait in the tree stand for game to come by. Such a feat is extremely impractical for a hunter confined to a wheelchair. A need exists to overcome this impracticality.
2. Description of the Related Art
Portable lifts are well-known in the art. However, all of the related art is deficient in some way which precludes their advantageous use in the above application. For example, small manually operated lifts, such as car jacks, do not have the required vertical travel and would be difficult to stabilize in the intended environment. Manually operated high-lift jacks, which are essentially larger versions of the auto jack, may have the required travel, but their larger size makes them difficult to transport, the manual operation results in a lifting which is unacceptably slow and tedious, and they can also be difficult to stabilize. Conventional lifts such as those used by roofers to shuttle material from ground level to a rooftop are also inadequate. These lifts are usually based on a long ladder, which is supported by leaning the ladder against a structure such as a roof edge. A platform is then run along the ladder. However, the ladder is longer than necessary since it must be leaned against the supporting structure, which can be problematic in the hunting application. Furthermore, such devices are not designed to be used in a near vertical orientation and they can be difficult to transport through wooded terrain. In addition, all of these lifts are designed to lift loads less critical than human beings and so many of them also lack adequate safety devices which would protect a passenger in the event that the lifting mechanism becomes inoperative.
At the other extreme of the related art are much heavier lifts. Examples of these would include forklifts and self-propelled platform lifts such as those used in warehouses and at construction sites. While these lifts have the required load-bearing capacity and vertical travel, they are grossly inadequate in other respects. Many of these lifts are designed only for use on smooth surfaces, such as a warehouse floor, a highway bed or a dockside pier, and would be totally unsuitable for use on rough terrain. This restriction applies both to the transportation of the lift and the manner in which the lift is stabilized. Furthermore, the lifts in these devices are already larger, heavier and more costly than is required for the current application, and the power source required for self-propulsion simply makes the device even larger and heavier. The result is a device which is too large and heavy for use in the hunting environment.
There are also a large number of lifts designed for increasing the mobility of the physically impaired, including the wheelchair-bound. However, these lifts also fall short of the required characteristics. First, many of them are not portable, the overwhelming majority being intended for use as a permanent entrance to a building or vehicle. Second, they have insufficient vertical travels. For example, lifts used with buses need only travel from the curb to the bus floor, a maximum of several feet. Third, many of the operating mechanisms are not suitable for use in a hunting environment. In any case, no lift for the physically disadvantaged combines the portability, flexibility, and lift range required.